1. Field of the Invention
The present invention relates to a liquid crystal display panel and, more particularly, to a liquid crystal display panel which is equipped with testing pads for electrically testing whether or not a conductive layer has been formed without any disconnection in the manufacture process.
2. Description of the Prior Art
For example, a liquid crystal display panel of active matrix type is equipped with transparent substrates which are arranged to confront each other through a liquid crystal and one of which is formed on its main surface at the liquid crystal side with matrix-arranged pixel electrodes and thin film transistors (or switching elements) arranged close to the pixel electrodes.
There are further formed a set of conductive layers made of scanning signal lines for applying a voltage commonly to the gate electrodes of the thin film transistors of each row, and a set of conductive layers made of video signal lines for inputting signals to the pixel electrodes of each column through the thin film transistors.
Here, the scanning signal lines are usually formed of a sequential laminate of an aluminum (Al) layer or an Al alloy layer and a transparent conductive film. This transparent conductive film is formed to protect the surface of its underlying Al layer or the like and is made of the same material as that of the pixel electrodes at the common step.
Moreover, the scanning signal lines are extended at one end to the region (as located in the periphery of a transparent substrate face), which is later cut and removed, and are commonly connected at the end, while testing pads are disposed at the other end for testing whether or not the scanning signal lines are disconnected after they have been formed.
Incidentally, the liquid crystal display device of active matrix type using the thin film transistors is known in the prior art, as disclosed in Japanese Patent Laid-Open No. 309921/1988 or on pp. 193 to 210 of Nikkei Electronics entitled "Active Matrix Type Color Liquid Crystal Display of 12.5 Type Adopting Redundant Construction" and issued on Dec. 15, 1986 by NIKKEI McGRAW-HILL, for example.